A magnetically shielded substrate with a layer of magnetic shielding material that has a squareness of from about 0.5 to about 1.0.
U.S. Pat. No. 6,506,972 discloses and claims a magnetically shielded conductor assembly containing a conductor disposed within an insulating matrix, and a layer composed of nanomagentic material disposed around the first conductor. The conductor has a resistivity at 20 degrees Centigrade of from about 1 to about 100 microohm-centimeters. The insulating matrix is comprised of nano-sized particles having a maximum dimension of from about 10 to about 100 nanometers. The insulating matrix has a resistivity of from about 1,000,000,000 to about 10,000,000,000,000 ohm-centimeter. The nanomagnetic material has an average particle size of less than about 100 nanometers. The layer of nanomagnetic material has a saturation magnetization of from about 200 to about 26,000 Gauss and a thickness of less than about 2 microns. The magnetically shielded conductor assembly is preferably flexible, having a bend radius of less than 2 centimeters.
The entire disclosure of U.S. Pat. No. 6,506,972 is hereby incorporated by reference into this specification. It is an object of this invention to provide a magnetic shield that is more effective than the magnetic shield disclosed in such United States patent.
In accordance with this invention, there is provided a magnetically shielded substrate assembly comprised of a substrate and, disposed over such substrate, a magnetic shield. The magnetic shield, when exposed to a magnetic field with an intensity of at least 0.5 Teslas, has a magnetic shielding factor of at least about 0.5. The magnetic shield is comprised of a film of nanomagnetic material comprising at least about 40 weight percent of nanomagnetic material with a mass density of at least about 0.01 grams per cubic centimeter, a saturization magnetization of from about 1 to about 36,000 Gauss, a coercive force of from about 0.01 to about 5,000 Oersteds, a relative magnetic permeability of from about 1 to about 500,000, and an average particle size of less than about 100 nanometers. The film of nanomagnetic material has a squareness of from about 0.5 to about 1.0.